Heretofore, flexible material such as fabric, plastic material, and the like has been spread on an elongated lay-up table by a conventional spreader which travels back and forth along the length of the table. Once the desired number of plies has been deposited on the table by the spreader, patterns are cut from the plies by hand operated cutting devices.
More recently, there has been great interest in utilizing a laser to cut patterns from flexible material. For the most part, the devices and methods developed by prior art workers were intended to utilize a laser to cut a single layer of fabric or the like. U.S. Pat. No. 3,761,675, for example, teaches such a system. The reference system utilizes a conventional cloth spreader held in a fixed position to deposit fabric upon a moving conveyor belt-type support at a rate compatible with the movement of the support. U.S. Pat. No. 3,764,775 teaches the use of a laser cutter and means to advance fabric thereto in intermittent fashion. The reference system utilizes a continuous conveyor or one or more carriages.
U.S. Pat. Nos. 3,811,554; 3,828,697 and 3,889,095 teach a laser cutting system for fabric whereby a single fabric ply is paid off a roll at a rate consistent with the movement of the support for the fabric. The support may constitute a segmented conveyor belt of honeycomb slats, or a slidable tray comprising a honeycomb structure supported on knife edge slats. U.S. Pat. No. 3,828,159 teaches a table surface for use in the laser cutting of cloth. The supporting table surface comprises a honeycomb structure backed by a heat absorbing and non-reflecting material.
U.S. Pat. No. 4,680,442 teaches an apparatus for cutting multiple layers of fabric. In this instance, multiple layers of fabric are disposed upon a honeycomb support. The honeycomb support, in turn, is mounted on a vacuum table connected to a vacuum source whereby smoke and debris from the multiple layers of fabric can be withdrawn and disposed of.
In most instances, prior art systems for cutting multiple layers of flexible material such as fabric have involved the use of a conventional spreader, or have been laid up by hand. Both operations are relatively slow.
In prior art continuous systems, utilizing a continuous support surface, it has been possible to provide a number of plies, but there must be a roll for each ply which is sometimes difficult to manage and which generally requires considerable floor space.
The present invention is based upon the discovery that if a conventional CNC (computerized numerical control) laser center, of the type having a cutting zone, a loading/unloading zone, and upper and lower carriages, each bearing a support pallet and each capable of being shifted between the cutting zone and the loading/unloading zone, is combined with a cutting and stacking machine of the type having a cutting and stacking section and a material supply section capable of handling one or more rolls of material, a simpler, faster and more efficient system may be achieved. Stacks of flexible material can be formed on each of the carriage pallets having a number of layers dependent upon the nature of the material, its thickness and the like. The plies of each stack may be of several different materials which can be stacked in a desired order, as will be set forth hereinafter. A flexible cover sheet is applied to each stack to assist in movement of the laser center cutting head assembly thereover. No vacuum is required to hold the plies in place and sufficient pressure may be applied on the stack by the laser cutting head assembly to reduce the stack thickness up to about 50% to keep the laser beam from being reflected between the plies. This compression of the stack occurs only at the vicinity of the laser beam.